Modern user devices such as phones (e.g., smartphones), tablets, notebooks, electronic readers and the like typically include, in addition to wireless communication capabilities, one or more sensors that can detect and/or infer the context of the device and, by extension, contextual information of the user. One example is the use of a position or location determining sensor such as one embodied as a global positioning satellite (GPS) receiver and sub-system. Another example is an orientation sensor whereby it can be determined how the user has oriented a display screen (e.g., longest dimension vertically or horizontally).
In addition to the large amount of personal data stored on these user devices (sms logs, call logs, contacts list, etc.) many sensors can be used to infer the location, context, personal habits, etc. of the user. All of this information has the potential to be exposed to privacy threats, such as third party applications (apps) that the user installs.